THIS WEEK IN THE WORKSHOP / SOLID WOOD
Give your wood
room to move.
Estimate seasonal width changes, compare the space at the wet endpoint, and keep the assumptions beside your attachment drawing.
Check a measured part ↓Private in your browser · eight source-linked species
The example is ready to edit. Valid changes stay in this browser when storage is available.
STATIC EXAMPLE / WHITE OAK (WHITE)
13.536 mm seasonal width change
600 mm measured at 8% MC; tangential model; 6–12% service range.
- Dry width
- 595.488 mm
- Wet width
- 609.024 mm
- Wet total clearance in 612 mm
- 2.976 mm
- Balance after 2 mm total reserve
- 0.976 mm
Approximate unrestrained movement. The fixed-opening calculation and centered reference do not specify the attachment.
Wood Movement Planner · Method v1 · 2026-10-11. Approximate unrestrained cross-grain movement, 6–14% wood MC. Source: USDA Wood Handbook FPL-GTR-282 (2021), Table 13–5 and Equation 13–3. https://research.fs.usda.gov/download/treesearch/62261.pdf
AN ESTIMATE YOU CAN TRACE
The coefficient.
The scenario.
The drawing.
Width change = measured width × coefficient × MC percentage-point change. Calculate each endpoint from the same current width; subtract dry width from wet width for the seasonal swing.
Wet clearance = fixed opening − wet width. Reserve balance = wet clearance − your required total reserve. Center and edge references describe assumed displacement, leaving attachment geometry for the actual drawing review.
By WoodCutTool editorial team · Reviewed 2026-10-11. Method v1 · next review 2027-04-11.
What does this wood movement calculator estimate?
Approximate unrestrained cross-grain width changes of the listed solid woods over an entered 6–14% wood moisture content range, using USDA Wood Handbook Table 13–5 and Equation 13–3.
Can I enter room relative humidity?
No. Enter wood moisture content, not air relative humidity. The tool does not predict a service range or an acclimation time.
Does the result specify an attachment or slot?
No. The opening is assumed fixed and the reserve is user supplied. Edge travel is displacement under an entered locating-reference assumption; it is not a slot length or construction approval.
Where is the project saved?
Valid drafts stay in this browser when local storage is available. Export JSON to restore the editable draft and CSV to retain a review. Project inputs are not uploaded.
How should I read “compare both”?
These are separate radial and tangential models. They do not establish statistical uncertainty bounds, the actual ring angle or a guaranteed movement range. The planner does not model warping, mixed-species glue-ups or restrained stresses.
SOURCE TABLE / AUDIT THE INPUT
Eight specific woods. Two directions.
USDA Wood Handbook, FPL-GTR-282, Chapter 13 (2021), Table 13–5 on page 13–17 and Equation 13–3 on page 13–16. Coefficients are per one MC percentage point, referenced to dimensions at 10% MC. We use the handbook’s approximate starting-dimension equation within 6–14% MC.
| Species entry | Radial CR | Tangential CT |
|---|---|---|
| White oak (white) | 0.00194 | 0.00376 |
| Red oak (northern red) | 0.00137 | 0.00304 |
| Sugar maple | 0.00165 | 0.00353 |
| Black walnut | 0.00190 | 0.00274 |
| Black cherry | 0.00126 | 0.00248 |
| Yellow-poplar | 0.00158 | 0.00289 |
| Eastern white pine | 0.00071 | 0.00212 |
| Douglas-fir (Coast-type) | 0.00165 | 0.00267 |
These coefficients estimate free solid-wood dimensional change. The local stock, moisture evidence, opening behavior and hardware detail require their own review. Values are not green-to-oven-dry shrinkage percentages.
FROM A NUMBER TO A REVIEWABLE DETAIL
Three field guides
Choose a Width Direction for a Wood Movement Estimate
Identify the measured cross-grain dimension, compare radial and tangential scenarios, and trace the exact species coefficient before planning a solid-wood part.
Read the guide →FIELD GUIDE / 02Record Wood Moisture Readings and a Service Range
Build a traceable wood-moisture input record with measured width, current MC, service endpoints, location and instrument notes before comparing seasonal dimensions.
Read the guide →FIELD GUIDE / 03Review Seasonal Clearance and the Attachment Reference
Separate total opening clearance, expansion from today and edge displacement, then carry a solid-wood movement estimate into a documented attachment review.
Read the guide →